During his championship reign, he was ranked as a top three pound-for-pound fighter and regarded as one of the best mixed martial artists in the world.
[11] His nickname Barão (baron), which predates his athletic career, was given to him by his grandmother after a character in the 1986 Brazilian soap opera Sinhá Moça.
[4] He started his career in Kimura Nova União, a sports school in Natal, Rio Grande do Norte, Brazil.
[4] In January 2010, Sherdog named him their top prospect in their list of "10 Brazilians to watch in 2010"[13] Barão was expected to make his North American, as well as WEC debut in a Bantamweight bout against Clint Godfrey on 20 June 2010 at WEC 49,[14] but Godfrey was forced from the card with an injury.
[15] Barão instead faced fellow WEC newcomer Anthony Leone at an agreed 142 lb catchweight.
[27] Barão was expected to face Ivan Menjivar on 7 July 2012 at UFC 148 to possibly determine the number one contender.
[28] Barão instead faced Urijah Faber for the Interim Bantamweight title after current champion Dominick Cruz was injured.
[29] It was originally scheduled to take place at UFC 148 however, due to an injury to headliner José Aldo (who was supposed to make a title defence in the event's main event fight), the Faber/Barão bout was moved to 21 July 2012 and headlined UFC 149 for the Interim Bantamweight Championship.
[33] McDonald was competitive with capable take-down defense and crisp boxing - particularly - in the first two rounds, but was worn down by Barão's more diverse skill-set as he mixed in knees and kicks standing, and often looked to take the fight to the floor (with success).
[35] Barão was scheduled to make his second interim title defense against Eddie Wineland on 15 June 2013 at UFC 161.
[38] Barão retained the title with a second-round TKO victory via spinning back kick and subsequent punches to the face.
[47] However, the day of the weigh-ins, Barão had to be admitted to the hospital as a result of his attempts to cut weight, and was removed from the card.
[62] Barão was briefly linked to a bout with Doo Ho Choi which was expected to take place on 15 April 2017 at UFC on Fox 24.
[63] However, as the announcement of the pairing began to circulate, Choi declined the bout, and as a result, Barão is expected to be rescheduled against a different opponent, possibly at another event.
[70] At weigh-ins, Barão weighted five pounds over bantamweight non-title fight limit of 136 and he was fined 30 percent of his purse to Ewell.
[75] Barão faced Douglas Silva de Andrade in a featherweight bout on 16 November 2019 at UFC on ESPN+ 22.
Barão was rumored to face fellow UFC-alum Sean Soriano in a bare-knuckle MMA bout at Gamebred Bareknuckle 5.
[89] Barão is scheduled to debut with the Global Fight League in his third bout against Urijah Faber at a to be announced date and location.
[90] Barão won a gold medal in the master 2 lightweight division of the IBJJF Fortaleza International Open on 24 June 2023.
[91] In July 2023, Barão announced that he had a grappling match with Charles Oliveira arranged for a future BJJ Stars event.